package main

/*
import (
    "pkg.jfrech.com/brief/internal/worlds"
)

// Exactly one pointer is non-nil. See [MessageIdOrOtherworldlyFile.Contract].
type MessageIdOrOtherworldlyFile struct {
    MessageId *messageid.MessageId
    OtherworldlyFile *worlds.OtherworldlyFile
}

// may panic
func (midOrOwf MessageIdOrOtherworldlyFile) Contract() {
    a, b := midOrOwf.MessageId, midOrOwf.OtherworldlyFile
    if a == nil && b == nil {
        panic("zero sum")
    } else if a != nil && b != nil {
        panic("overzealous sum")
    }
}

func (midOrOwf MessageIdOrOtherworldlyFile) IsMessageId() bool {
    midOrOwf.Contract()
    return midOrOwf.MessageId != nil
}

func (midOrOwf MessageIdOrOtherworldlyFile) MessageId() messageid.MessageId {
    if midOrOwf.Contract(); midOrOwf.MessageId == nil {
        panic("!IsMessageId")
    }
    return *midOrOwf.MessageId
}

func (midOrOwf MessageIdOrOtherworldlyFile) IsOtherworldlyFile() bool {
    midOrOwf.Contract()
    return midOrOwf.OtherworldlyFile != nil
}

func (midOrOwf MessageIdOrOtherworldlyFile) OtherworldlyFile() OtherworldlyFile {
    if midOrOwf.Contract(); midOrOwf.OtherworldlyFile == nil {
        panic("!IsOtherworldlyFile")
    }
    return *midOrOwf.OtherworldlyFile
}
*/